DE1668735A1 - Process for the production of adiponitrile - Google Patents

Description

Process for the production of τοη adiponitrile

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Bio present invention relates to a process for the production of adiponitrile by reductive diinerlation of Acrylonitrile »In particular, the present invention relates to a process for the preparation of adiponitrile by reductive Dimerization of acrylonitrile using a metal amalgam in the absence of external electrical currents ο

On the basis of the prior art, there are two processes for the preparation of adiponitrile by reductive dimerization of Acrylonitrile known. One of them is a process for producing adiponitrile by electrolysis of an aqueous one Solution of acrylonitrile for hydrodimerization and the other

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OBIQINAL

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let a process for its manufacture ciürsh implementation of an alkali metal algae from an aqueous solution of Acrylonitrile ο

In the case of such an electrolyte corner process, however, let eo difficult »to widen the area of the elephantolysis bath so t that the process can be used industrially * and further disadvantages are »that the hectrolysis pre-φ direction and the required electrical energy expensive

are ο

fia from known values of the previous Amalgainverfahreno apparent "fall-products of propionitrile, polymers etc. and in this way 1st yield en Adiponitrile bezogst on consumed Aorylnitriljsebr low" Further, the amalgam efficacy (amalgam efficiency) is very low "The AmalgamwirksaBSkelt is the percentage represents "Real adiponitrile yield ₍ based on the theoretical adiponitrile yield from the theoretical amount of hydrogen _p that is triggered by the actually consumed amalgam" two hydrogen atoms * So theoretically every mole of sodium consumed produces 1/2 mole of adiponitrile

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BAD OBlGWAL

For example, in the hydrodiaerization of acrylonitrile in aqueous solution using sodium amalgam the amalgam potency is less than about 20 pounds and eelbat at Use of an expensive metal amalgase, such as Rubidium · * and Cesium amalgam »the Aalgam effectiveness was the highest8 £ 32» Therefore the earlier amal gas process has not found its way into industrial use.

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The subject of the present invention is a new one

Process for the industrial division of adiponitrile under Using a metal amalgama to create eu

Another subject is »new catalysts for the production of adiponitrile using a metal amalgam to accomplish.

Another subject is it 'in various ways To produce commercially useful adiponitrile by acidifying the adiponitrile yield and the Ajaalganmirkeemkeitt while lifting reactions are suppressed.

-Another subject is »new reaction procedures below Using a new catalyst to create "

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Another subject is “new methods of separation and purifying the adiponitrile produced using a metal amalgam

Ea now became a process for the production of adiponitrile that unites the above properties »created» whereby acrylonitrile is bydrodiraieriert by contacting a metellamalgam in the presence of a catalyst with an aqueous acrylonitrile solution in the range from pH 2 to 12, The process uses an acid or a substance that has acidity in the aqueous solution »used» around the To control the pH value of the reaction solution »and if necessary» is used to dissolve the acrylonitrile in water solvent used

In the earlier amalgain process, usually polymeric ones are used By-products generated »when the amalgam is in a system such a concentration of acid decomposes »that the pH the aqueous aoryl nitrile solution is 1 or less. on in this way not only is the Adiponitrllau hive reduced » but the nascent hydrogen generated by the dissociation of the amalgam in the reaction solution cannot either used for the reductive coupling of the Aery! nitrile » since the hydrogen atoms combine to form molecular hydrogen and escape from the system »As a result, the Extremely low amalgam effectiveness

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In the present invention, no polymeric by-products - as in the case of strong acidity - are inherited because they are calibrated daa amalgam in the aqueous adiponitrillöming at one pH of 2 to 12 decomposed In addition, calibrate to unite the hydrogen atoms do not become molecular «hydrogen» but

* ■
They have an effective effect on the acrylonitrile, which is reductively coupled, resulting in high levels of adiponitrile

At a pH value of less than 2, the production of Hydrogen gas at high speed, at a pH However, if more than 2, the rate of generation of the hydrogen gas becomes low and the amalgam efficiency becomes “Very much improved” Furthermore, at a pH value above 12, expensive by-products and the Adiponitrile yield is reduced. Halfway through the sea it is necessary to keep the pH value of the heating solution in the range from 2 to 12 to hold ο

It was also found that in the Reaction of the reductive dimerization of acrylonitrile for Manufacture of adiponitrile setraalkylarsonium compounds are very effective as a catalyst "

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The tetraalkylarsonium compounds used according to the invention as a catalyst sm correspond to the following formula

wherein R ¹ , R, R * and R * are identical or different alkyl. '

remains with. V to -20 carbon atoms and / "X _- Z""an inorganic or organic anion, wosu 01", Br "*» J ** »SO ^, RSO ^", where R is an alkyl radical with 1 to 4 carbon atoms is, SG3äT, OH ", PO ^" * "", and any sulfonic acid anion, carboxylic acid anion, benzoic acid anion and phosphone.tanion, mean «.. -

Examples of tetraalkylarBonium cations £ ~ R R r'r ^ As _- T ⁺ are as follows

Tetramethylarson lumcation _ SetraSthylarspnium cation

Tetra-n-propylarsonium cation

Tetra-propyl arsonium catalyst

Tetra-n-butyl arsonium catalyst

Tetra-tert-butylarsonium cation

Methyl triethylarsonium ion

Dimethyl-disthylarson lumcation

Ethyl trimethylarsonium cation

Benzyl ^ trimethylarsonium cation

Benzyl-triethylarsonium cation Xthyl-tri-n-propylarsonium cation 820/2191 "i.

ORIGINAL

1663735

Ethyl-dimöthylheiadecylaroneiaSication ■ '- Trimethyl hexadecylereonium catalyst Trimethyl-ß-hydroxyethyl aromatic cation Trinethyl-ß-broraäthylareoniuakatiön Trimethyl-dodecylereociuakation Trimethyl-octadecyl-arsoniumkaticn and Trietnyl-n-ootylareoniuajkation

It is believed that the part which acts as a catalyst in the above hydrodimerization reaction is a tetraal'-ylarsonium cation in the tetraalkylarsonium compound. That holest, it is believed that the fetralkylarsoniuakation, which is a catalyst, acts on the mercury or Amalgam surface is adsorbed because there are two acrylonitrile « molecules, which are also adsorbed on the QueoksiltäerobegfläChe, and that it accelerates the hydrodimerization reaction with the production of adiponitrile.

In the present invention, such an aromatic arsenic compound as tetraphenylarsonium as has been shown to be ineffective in preventing this.

Among those used according to the present invention xu TetraalkylareonlunTerbindungen are especially excellent and tetramethylareonium salt and tetraethylarsonium salt

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effective. When using ϊβtra-n-propylarsonium salt or! Detra-n-butylarsoniumealz, the effect was slightly less Furthermore, such an asymmetric tetraalkylarsonlum-8 was al z, such as methyl-trläthylarsonlumealz or Dimethy1-diethy1-arsoniumeals, effective. Furthermore, when the catalyst was used as an arsonium salt, it decreased the effect an alkyl radical with substituents »such as a halogen or Hydroxyl radical, contained "

Bb is important to note that in the present invention using the new catalyst the generation

by-products is prevented and the amalgam efficiency is considerably increased, or the hatred of the effective use of the nasal hydrogen produced by the dissociation of the amalgam is increased. In the present invention, it is effective to add about 0.0001 moles of catalyst per column of acrylonitrile to the reaction solution. With the addition of more than about 0.001 moles of catalyst per mole of acrylic W nitrile to the Reaktionelb'eung, the generation of tone propionitrile # expected by side reaction to less than 1 · ^ Sew inhibited and it may be a Adiponltrilausheute near 100 wt. V / ground ; however, it is not necessary to add more than 0.01 mole of catalyst per mole of acrylonitrile.

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BATH ORIGINAL

When the aoryl nitrile concentration in the aqueous solution is low, in the above-mentioned reaction, side reactions such as a blink reduction in the production of propionitrile and the union of two hydrogen atoms generated by the dissociation of the metal amalgam to generate gaseous oxygen are generally more likely to occur . It is therefore necessary that the acrylonitrile * concentration in the aqueous solution is higher than about 5 i> j. _e t,

In the reaction mentioned above, the tetraalkylaronaone compounds are not only catalysts, but also solvents which dissolve large amounts of acrylonitrile. Therefore, favorable results are obtained "even if no other solvent is used". However, if higher amounts of acrylonitrile are to be dissolved in the aqueous solution, use creates a solvent that dissolves the acrylonitrile in water and does not inhibit the above reaction, better effects. Such solvents include, for example Monoalkylamide as methylformamide, Äthylformamid, Hethy1-acetamide and Äthylacetamid, dialkylamides such as dimethylformamide and Diäthylftoetamid _e Hexaalkylphosphamide as Hexamethylphosphamld and Hexaäthylphoepharaid, Dialkylsulfoxyde as diynes thy Isulf oxide and Diäthylsulf oxide, Dialkylsulf one as Bimethyleulfon and Diethyl sulfone, aliphatic alcohols such as methanol, xthanol, xsopropanol and n-butanol, acetone, N-methylpyrrolidone and acetonitrile,

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BATH "ORIGINAL.

the aforementioned catalysts and if necessary the above-mentioned solvents are used, the acrylonitrile becomes adiponitrile with a far higher yield and amalgam effectiveness than it was available so far "

The pH of the. Heating solution can be added by adding an organic

or.r ■ -.

nisohen acid / an inorganic acid such as hydrogen chloride acid, sulfuric acid, acetic acid or sulfonic acids or any other substance that has acidity in the aqueous solution generated »like carbon dioxide or soybean dioxide, in the area • w- 2 to 12 are held ·

As a substance containing hydrogen required for hydrogenation in the above-mentioned hydrodimerization reaction supplies »water is very suitable. Even if an alcohol such as methanol or ethanol, or a mixture of water and an alcohol is used, but adiponitrile, can be obtained in favorable yield. Furthermore can also an acid such as acetic acid or formic acid can be used, although the yield will be somewhat lower.

According to the present invention, the composition exists the reaction solution preferably from 5 to 50 <£ acrylonitrile, 5 to 40 # water and 25 to 80 # solvent, on a ffev / icht basis. .

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■ The reaction temperature should be between the boiling point and the boiling point of the reactive solution. Ss However appropriate the reaction temperature between 10 and 50 ⁰ C "u keep inhibit the reductive Dlmerislerung of acrylonitrile accelerate au and any Webenrepktionen eu"

The amalgam to be used according to the present invention is an alkali metal or alkaline earth metal amalganu Hence Amalgams such as those of rubidium and cesium can be used However, amalgams are due to sodium »and potassium most suitable for their economic efficiency.

Regarding the concentration of the metal amalgam used in the present invention, it was found that the yield and amalgam efficiency when the reaction was carried out using an amalgam having rivet metal concentrations such as 0.01 to 0.05 wt the Aaelgamgewioht, 2ifa _r hooh are, however, a will: required certain amount of alkali metal in the amalgam mercury meng "then be very big and very uneconomical. The present invention also provides a method of overcoming this problem as set out below "

To do this let us execute: If mercury first with the reaction solution is held in contact and then the amalgam

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BATH ORIGINAL

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this mercury is added - even when in use of a metal amalgam with relatively high alkali metal concentrations, such as 0.3 to 0.7 wt. 96, based on the Amalgam - the amalgam comes in diluted with the mercury Perm be in contact with the reaction solution and therefore get the same effects «as when using a Amalgams with low alkali metal bound ions. Because now an amalgam whose alkali metal concentration is tO times and higher than that in general can be used Amalgam concentration used in known amalgam processes can be that for a given amount of alkali metal required amount of mercury 1/10 or less that in the known method amount required and the The present invention is industrially feasible.

An example of a device used in the present invention will be described in more detail with reference to Pig. I described. Mercury 4 is first placed on the bottom of a reactor 5, which is provided with a reflux condenser 1 and a stirrer 2. An aqueous solution containing acrylonitrile, a solvent and a catalyst are added to the mercury 4, thus creating a reaction solution 6. In this way, the reaction solution 6 is prevented from entering the amalgam drip tube 5.

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In the reaction solution 6, a thermometer 7 and a pH heterodyne electrode 8 introduced to follow the reaction and control. When the amalgam 9 is given through the amalgam drip tube 5 directly to the mercury 4, comes the amalgam with the reaction ons solution 6 in contact after ea has been diluted with the mercury 4; Since the amalgam 9 is added through the drip tube 5, the amalgam dissociates, and the pH of the reaction solution 6 gradually rises « Therefore, substances in the reaction solution become acidic and capable of neutralizing the alkali generated by the amalgam dissociation through the dropping funnel 10 or the inlet pipe 11 is added to the reaction solution 6 in order to keep the pH value of the reaction solution 6 at 2 to 12 Ss is desired, the reaction solution 6 and the mercury stir well with stirrer 2 during the reaction «

If 0.015 to 0.3% by weight of metal amalgam is used, an apparatus as shown in FIG. 2 can be eminently suitable for carrying out the reaction economically. That is, it is a method in which a metal amalgam in particulate form is finely granulated and the amalgam particles are allowed to descend from an upper zone of the reaction tower containing an aqueous nitrile solution. The production method according to the invention with the tower-type reactor is explained below with reference to a drawing in FIG. 2

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Let cine electrolytic apparatus is shown in which a metal amalgam with a metal concentration of 0.015 to 0.356 is preferably prepared. This amalgam enters a reaction tower 4 through a tube 2. The reaction tower is in the shape of a cylinder, a square column or a multi-cornered column and does not need to contain a conventionally used deamalgamation accelerator such as graphite, but it can be filled with a solution fine-granulated as 3.5 mm. In this case, the fine granulating device can also be located above 3 or below the level of the reaction solution. As a method for fine granulating the amalgam, for example, a drop-in, injection, three-phase flow or colliding method is used. The fine amalgam particles of less than 3.5 mm will be essentially completely decomposed as they descend through Part H. The mercury is collected through part 7 in a Sanmelrohr 8 and circulated through a pipe 9 and a mercury pump 12 to the device 1 · 10 is an inlet pipe for the Reaktlonslöaung »which is made by dissolving acrylonitrile in an aqueous solution of the catalyst and / or solvent was · The amalgam hydrogenates acrylonitrile during its stay in part 14 and dimerizes adiponitrile and discharges it from the system through pipe 13. 5 and 6 are

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"'- BADORiGiNAL

Inlet and outlet pipes for carbon dioxide, preferably to neutralize dee by entamalgarizing the amalgam generated alkali is required. 11 is an Auelaesrohr to drain the generated inorganic salt as a slurry. According to this procedure, the adlponitrile yield is and amalgam effectiveness as high as in the case of the in Hg «1 Reaction shown · It is therefore an industrially valuable process.

After hydrodimerization of the aoy! Nitrile becomes a metal by-product by filtering the reaction solution separated and the adiponitrll weÄ then by distillation won. For example, if acrylonitrile using an alkali metal amalgam and carbon dioxide as the acidic Substance is hydrodimerized, results as a lift product an alkali metal bicarbonate. In this case a small amount of the alkali metal bicarbonate in the PiItrat, whereby the bio carbonate during the distillation unwanted lifting reactions, the ethylene anhydrin and bie- (ß-Qyanäthyl) -ether -etc. generate, promote. Therefore, it is preferred to remove the bio-carbonate from the obtained substrate for removal small amounts of carbonate from the resulting piltrate is the Piltrate is neutralized by adding an acid and then adiponitrile is obtained by distillation «Or, adiponitrile is extracted from the resulting piltrate with acrylonitrile, the small amount of alkali metal bicarbonate contained in the extract

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remains, is neutralized with an acid or, removed by ion exchange resin treatment and adiponitrile is then obtained by distillation.

The amalgam process according to the invention differs from the electrolysis process in »that the catalyst used need not be an electrolyte »which develops a high electrical conductivity in aqueous solution and which should be stable under an electrolytic voltage · The The reason is that in the amalgam process no electrical current is passed through the aqueous aoryl nitrile solution su needs to be. Therefore, the present invention is of the electrolysis process »according to which an electric current is passed through the aqueous acrylonitrile solution, fundamentally different.

The following examples illustrate the invention without its Restrict application

example 1

50 om ^ mercury were first put at the bottom of a reactor, as in Pig. 1 shown, given the. a capacity of 500 cm 'possessed a mixed solution of 35 g of acrylonitrile, 0.2 g tetramethylarsonium jödid, 25 g water and 40 g dime thy 1-

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BATH ORIGINAL

formamide was then added to the mercury and gradually stirred. 214.0 g sodium amalgam of a sodium concentration of 0.452 · fi were dropped through the amalgam drip tube 9 for about 10 minutes in the mercury At the same time, a ~ 6n 0hlorwasserstoffsäurelösung through the dropping funnel 10 as required in the Reaktionelöeung dropwise. The reaction was carried out at 25 to 35 ^° C. while the pH of the reaction solution was kept in the range of 9-1 with HCl.

After the reaction, the reaction solution was with about the diluted twice the amount of distilled water. You diluted Solution was extracted five times with 50 carbons of Diehlonaethane each time. Bae extract was washed once with 100 cm - distilled water and dried over potassium carbonate obtained adiponitrile and unreacted acrylonitrile were quantified by gas chromatography · As a result 2.19 g yield of adiponitrile were obtained and at all no by-product observed. The yield of adiponitrile based on acrylonitrile consumed was about £ 100 The adiponitrile yield based on sodium amalgam consumed (amaleam potency) was about 96.5 #.

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Example 2 .

Example 1 was prepared using 210.1 g of Kaliurara algara with a potassium concentration of 0.310 wt. # Instead of the in. Example 1 used sodium amalgamates repeatedly. 0.78 g yield of adiponitrile was obtained and no by-product was observed * The yield of adiponitrile was .100 $> and the amalgam potency was 86.7 &>

Example 3

Example 1 was repeated using a reaction solution containing 35 g of acrylonitrile, 1.0 g of tetramethylarsonium iodide, 25 g of water and 40 g of dimethylformamide, 206.5 g of sodium amalgam having a sodium concentration of 0.452 wt. ^ And CO ₂ -SaB instead of the ön -HCl solution were used ι the COg gas was blown through tube 11 into the reaction solution. The pH of the solution was maintained 8-10 »2.15 g Adiponitrilausbeute was obtained, and no by-product observed" The Adiponitrilausbeute 7 was about 100 ° and the amalgam effectiveness was 98.2? C _e

Example 4

Example 1 was made using a mixed solution of 1 g tetraethylareonium chloride, 25 g water, 40 g dime thy 1- and 55 g of acrylonitrile repeated as the reaction solution,

208.5 g of sodium amalgam having a sodium concentration of 0.452 wt. # and 0O ₂ -SaS, as described in Example 3, were used. 2.19 g AdI ponitr house booty was obtained and no byproduct was observed. The adiponitrile yield was about 100 # and the amalgain activity was 99 »2 £ ·

Example 5

Example 1 was repeated using a mixed reaction solution of 35 g of acrylonitrile, 40 g of dimethylformamide, 1 g of methyltriethylarsonium iodide and 25 g of water, with 210.2 g of sodium amalgam having a sodium concentration of 0.452% by weight and CO ₂ gas, as described in Example 3 , were used "2.04 g Adiponitrilausbeute was obtained and 0.02 g Fropionitril was recognized as Kebenprodukt · the Adiponitrilausbeute was more than 99 ^ t the Froplonitrilauebeute was less than 1 $> and the amalgam effectiveness was 91 * 3 #.

Example β

Example 1 was repeated using a mixed reaction solution of 35 g of acrylonitrile, 40 g of dimethylformamide, 1 g of triethyl-n-octylarsonium iodide and 25 g of water, 20710 g of sodium amalgam having a sodium concentration of 0.452% by weight and 0O ₂ gas, as in Example 3 were used. 1.98 g yield of adiponitrile was obtained and

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0.02 g propionitrile would be observed as a by-product. The Adiponitrilausbeute was 99 '0 $> and Amalgamwlrkaarakelt was 90.2 jC.

Example 7

Example 1 was repeated using a mixed reaction solution of 35 g of acrylonitrile, 40 g of dimethylformamide, 1 g of tri-methyl-β-bromoethylarsonium bromide and 25 g of water, 206.5 g of sodium amalgam having a sodium concentration of 0.452 Sew. # And CO ₂ -SaS as described in Example 3 were used. 1.65 g of adiponitrile was obtained and 0.13 g of propionitrile was obtained as a by-product. The Adiponitrilausbeute was 92.7 $> and the amalgam effectiveness was 75.3 ^.

Example 8

A reaction solution, 30 S acrylonitrile and 0.2 consisted of 45 $ dimethyl sulfoxide, 25 ^ water? I> Tetraäthylarsoniumiodid was mm in a Turin device having a diameter of 30 and a FlUeeighöhe of 700 mm as shown in Fig. 2, introduced "From the lower part 6 of the tower 14, carbon dioxide CO _{2 was} continuously blown in to adjust the hydrogen ion concentration during the reaction time."

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A sodium concentration of 0.069 Qew, jC obtained by an electrolytic process using mercury as a

Electrode had been prepared, dropped into the reaction solution at a rate of 2 kg / minute and allowed to react for 1 hour «while the pH was kept at 8.5 to 9» 5. The temperature was kept at 40 to 42 ^° C. during the above-mentioned reaction. The average grain diameter of the amalgam was 1.3 mm. Hach completion of the reaction was the. Reaction reading extracted with dichloromethane · In the quantitative analysis of the extract by gas chromatography, 181 g of adiponitrile were obtained. In this case, no! Generation of propionitrile, amines "the Entamalgamierungswert of AmalgamsY" (inlet amalgam concentration) - (Auela8saraalgarakon8entration) / Einla88amalgamkonzentration χ 100 ^ 7 was 98 $> and, Amalgamwirksanb · Celtic (for Hydrierdimerisierung of Aory nitrile required Waeserstoffmenge / duroh the 'Entamalgamierung the amalgam generated hydrogen quantity χ 100) was 98 $ ·

Example 9

In the same reaction apparatus as in Example 8 was a sodium amalgam and granulated into a reaction solution dripped »those made of acrylonitrile, dimethylformamide, water and

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a Tetraäthylarsoniumjodidkatalyeator existed while carbon dioxide was blown 00g. Saohdem dae Ede lifting Natriumbioarbonat product formed was separated by filtration "was a BND reaction filtrate obtained with a pH value of ~ 9 ₉ 5, which was saturated with Hatriumbicarbonat and 6.7 # acrylonitrile, 54.0 $ dimethylformamide, ί 24.3> Adiponltril, 14.8 f> Wassert 0.2 4> TetraäthylarBoniumjodid and some by-product, such as Froplonitril contained. 3 Co ⁵ In hydrochloric acid was added to 300 g of this reaction filtrate so that the pH was 7.2. Acrylonitrile and dimethylformamide were then obtained by distillation under normal pressure. The AdIponitrII was obtained by distillation under reduced pressure of 3 mmHg. The AoryInItrilausbeute was 96.8 ^ that Dimethylformamidausbeute was 99.0 $> and Adiponltrilausbeute was 99.2 #.

Example 10

According to the same reaction process as in Example 8, a final reaction filtrate was obtained in a reductive dimerization with a granulated sodium amalgam, which consists of 15.2 ^ acrylonitrile, 14.8 ^ adiponitrile, 45 % dinethyl sulfoxide, 24.7 ^r / o Y / water, 0 * 2 56 tetraethylarsonium iodide and 0.14 ^ sodium bicarbonate. As 72.6 g of acrylonitrile and 117.2 g

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Water to 206 g of this were placed end Reaktlonsfiltrate, the PiItrat separated into two Sohiohten. The organic layer of 121 g contained 65.1 # acrylonitrile, 21.7 $ adiponitrile, 8.8 # dimethylsulfoxide, 4.4 $ water and 0.008% Natriumtiiearbonat. The aqueous layer of 273 g β besäe a composition of 9.2 # acrylonitrile, 1.5 $> adiponitrile, 30,1? £ dimethylsulfoxide, 58.2? 5 Water, 0.15 i> Tetraäthylarsoniumjodid and 1.0 f of sodium bicarbonate “ That holest, $ 96.5 sodium bicarbonate had migrated into the aqueous layer and # 86.5 adiponitrile had migrated into the organic layer.

3.8 onr 1/1 on hydrochloric acid was added to the above-mentioned extracted organic layer so that the pH was 7.2. Then acrylonitrile and water were distilled under normal pressure. Dimethyl sulfoxide and adiponitrile were distilled under reduced pressure. The yield of acrylonitrile was 96.6% . The dimethyl sulfoxide yield was 99.1 #. The adiponitrile yield was 99.4%.

Example 11

1000 cm 'the extracted organic layer, which was obtained in Example 10, through an ion exchange column packed with 100 cnr a Kationenauetauschharzes

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BAD ORIGWAL

(Amberlite IR-120) was charged for 0.5 hours (at a space velocity of 20) · At the Distillation of this ion exchange resin treated solution in the same manner as in Example 10 was Aoryl nitrile yield 97.2 #, the dimethyl sulfoxide yield 99 »19 ^ and the adiponitrile yield £ 99.3.

Controlι

Upon distillation of the extracted organic layer obtained in Example 10 as it is, without neutralization with acid and without treatment with the ion exchange resin, the aoryl nitrile yield was 84.2%, the dimethyl sulfoxide yield was 93.4%, the adiponitrile yield 89.8% the distillation residue rose to 4 ^, based on the extracted organic layer.

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BATH ORIGINAL

Claims (1)

Claims 1. Process for the preparation of adiponitrile by reductive dimerization of acrylonitrile, characterized in that an aqueous acrylonitrile solution with a metal amalgam from the group of alkali metal amalgams and brodalkali metal amalgams and an acid from the group of inorganic acids, organic acids or substances which are capable of creating acidity in an aqueous solution, reacted in the presence of Tetraalkylarsonlumverbindungen as a catalyst, the pH of the reaction solution to 2 to holds. 2. The method according to claim 1, characterized in that an organic solvent is added to the heating solution to dissolve the acrylonitrile in water. 3 · The method according to claim 2, characterized in that the organic solvent is selected from the group consisting of monoalkylamides, dialkylamides, dialkylsulfoxides, dialkylsulfones, hexaalkylphosphamides, aliphatic alcohols, acetone, N-methylpyrrolidone and acetonitrile. 109820/2191 4 «The method according to claim 1, characterized in that daas the metal aralgam is selected from the group sodium amalgam and potassium amalgam 5. The method according to claim 1, characterized in that the metal amalgam in a concentration of 0.015 to U, 7 wt. # Is added to the reaction solution. 6. The method according to claim 1, characterized in that 0.0001 to 0.01 hol of the catalyst per hol of acrylonitrile be added to the reaction solution. 7. The method according to claim 2, characterized in that the reaction solution 5 to 50 pounds of acrylonitrile, 5 to 40 # Water and 25 to 80 # of the organic solvent, on a weight basis, contains 8. The method according to claim 1, characterized in that the reaction temperature is set to 10 to 50 ° 0. 9. The method according to claim 1, characterized in that the catalyst has at least one tetraalkylarsonium compound the following formula 109820/2191 SAD ¹ R ² R ⁵ R ⁴ AbJ ⁺ where R ¹ , R ² , R ⁵ and R * are alkyl radicals with 1 to 20 carbon atoms and C ^ -J " ^a JtoiOÄ« * ■ * · ^Γ Group 01 ", Br", J ~, SO ₄ """ , RSO ^ ", where R is an alkyl radical with 1 to 4 carbon atoms, SCIT, OH ~, PO ₄ """, sulfonic acid anion, carbonic acid anion, benzoic acid anion and phosphonate anion. 10. The method according to claim 1, characterized in that the Acid from the group of hydrochloric acid, sulfuric acid, Acetic acid, sulfonic acids, carbon dioxide and sulfur dioxide is selected. 11. The method according to claim 1, characterized in that the implementation by importing mercury into the reaction solution and anechlieesende directly · adding the amalgam to the Mercury is carried out. 12. The method according to claim 1, characterized in that the reaction is carried out by dropping alkali metal amalgeateilohen from an upper part of a reaction tower into the reaction solution and introducing carbon dioxide aue a lower one Part of the reaction towers carried out into the reaction solution will· 10 9 8 2 0/2191 ** D. 13 · The method according to claim 12, characterized in that the alkali metal amalgam concentration la range ron 0.015 up to 0.3 Otw. ^. 14 · Method according to claim 1, characterized in that after the reaction by nitrating from the reaction solution a Metallealz is separated and then adiponitrile is obtained by distillation 15 · The method according to claim 1, characterized in that after the reaction using an alkali metal amalgam as metal amalgam and clay, carbon dioxide as a substance capable of creating acidity, by filtering out the reaction solution separated an alkali metal bicarbonate the resulting filtrate is neutralized by adding an acid and then adiponitrile is obtained by distillation will. 16. The method according to claim 1, characterized in that after the reaction using an alkali metal amalgam as a metal amalgam and τοη carbon dioxide as a substance that leads to Creation of acidity is able to separate an alkali metal bicarbonate from the reaction solution by filtration is, adiponitrile with acrylonitrile from the resulting 109 820/2191 Piltrate is extracted, the resulting extract neutralized by adding an acid and then by adding adiponitrile Distillation is obtained. 17 · The method according to claim 1, characterized in »that after the reaction using an alkali metal amalgam as the metal amalgam and carbon dioxide as the substance, capable of creating acidity, an alkali metal bicarbonate is separated from the reaction solution by filtration, adiponitrile is extracted with acrylonitrile from the resulting filtrate, the resulting extract treated with an ion exchange resin and then adiponitrile is recovered by distillation. 109820/2191